Connection of electrically insulated high-voltage conductors



Dec. 20, 1966 J. c. CLASON ETAL 3,293,354

CONNECTION OF ELEGTRICALLY INSULATED HIGH-VOLTAGE CONDUCTORS Filed Dec. 19, 1962 i 2 Sheets-$heet l INVENTORJ 17; C. C 22807? 515271 164 6. F/ijssw ATTORNEYS 0, 1966 I J. c. CLASON ETAL 3,293,354

CONNECTION OF ELECTRICALLY INSULATED HIGH-VOLTAGE CONDUCTORS Filed Dec. 19, 1962 I 2 Sheets-Sheet 2 i n in! i&

\ jh j i ,/6 i IF. I 17 14- H l -/4 l 1 i E 1 INVENTORS TEvz C. C 26250 ATTORNEY! United States Patent ration Filed Dec. 19, 1962, Ser. No. 245,930 Claims priority, application Netherlands, Dec. 20, 1961,

0 3 Claims. (01. 174-84) The invention relates to a connection of electrically insulated high-voltage conductors, comprising an electrically loaded gap between insulating parts added to said conductors, which parts consist of solid insulating material, such as casting resin, a flexible insulating filler under pressure being present in the gap.

Connections of this kind are known from the German printed application 1,027,759, of April 10, 1958, in which is discussed a metal-enclosed switching and distributing apparatus composed of several detachable high-voltage members and devices, in which apparatus a solid or liquid insulating filler under pressure is present in the gaps formed between the insulations of the various components. As appears from the various figures of this publication, for the formation of the gaps the insulating parts of the'equipment are constructed substantially in such a way that the externally conical end of one part fits into the internally conical end of the other part. Furthermore FIG. 7, among others, shows an isolating switch embedded in casting resin, the insulation of which is equipped at each end with a detachable cylindrical part so as to make the embedded parts accessible. The gaps formed between these cylindrical parts and the rest of the switch insulation are filled with a liquid insulating material.

Now the invention furnishes a connection of a new type, which differs from the conventional connections in that in the connection according to the invention with insulating parts having transverse dimensions remaining substantially constant over the entire length of the gap formed between them one of the insulating parts is equipped with an outer sheath of filler material, which sheath is anchored to its free end, the outer dimensions of said sheath being larger than the inner dimensions of the other insulating part, and has been inserted, together with said sheath, into the latter part so tightly that the air between the filler sheath and the insulating parts has been expelled.

In order to prevent the filler, which is compressed in the gap as the connection is made, being forced out through slots at the ends of the gap, the insulating pants are preferably constructed in such a way that the gap present between them forms a space that is closed at least at one end, while the filler sheath is kept under pressure in this space by a force derived from a compression spring.

To this end the filler sheath, which has to be anchored to the end of the part in question since otherwise it will be rolled back when the connection is telescoped together, may advantageously be cup-shaped, the bottom of the cup forming the anchorage. The removal of the air between the bottom of the cup-shaped filler sheath and the adjacent insulating parts can be provided for by one or more special measures.

As to the expulsion of the air present between the parts, which, in particular in the form of small air occlusions, may give rise to undesirable ionization effects, reference may be made for completeness sake to the Dutch patent specification 55,688 of November 16, 1943, from 3,293,354 Patented Dec. 20, 1966 which it is known to make use--for the connection of two rubber cables for instance-of connecting members of insulating material surrounding the cable ends to be connected, said members having contact surfaces directed transversely to the core of the cable at least one of which contact surfaces is flexible and forms with the other contact surface an acute angle opening from the centre of the cable towards the outside of the cable, said angle disappearing under a pressure compressing the two surfaces. As the contact surfaces are compressed the air between them is expelled towards the outside of the connection. A connection in which the insulating material has to be introduced as a filler into a gap is not discussed in this patent specification.

The invention will be explained more fully with reference to two embodiments, which are illustrated in a drawing, in which:

FIG. 1 is a cross-section of a connection of two conductors embedded in insulating material.

FIG. 2 is a three-phase construction of a connection between a cable not filled with oil and an embedded conductor extending beyond an insulating part.

FIG. 1 shows two insulating parts 1 and 2, in each of which a conductor 3 is embedded. The conductors 3 are interconnected by means of a conductor 4 which may be hollow and cylindrical, for instance, said conductor 4 being enclosed in a cylindrical insulating part 5. The insulating part 5 is fitted at both ends with a cup-shaped sheath 6 of flexible insulating material, such as butyl rubber, neoprene, or the like and has been inserted tightly, together with said sheaths 6, into likewise cylindrical spaces in the insulating parts 1 and 2. The thickness of the material of the sheaths 6 is so chosen that the outer diameter of the part 5 with the sheath 6 fitted thereon is larger than the inner diameters of the spaces in the parts 1 and 2, in consequence of which the air between the sheaths 6 and the insulating parts 1, 2, and 5 is expelled as the connection is telescoped together. In order to facilitate assembly and ensure as complete an expulsion of air as possible the sheaths 6 are lightly greased beforehand, on the outside as well as on the inside, with silicone grease, for instance.

In order to prevent the filler sheaths 6, which therefore are under pressure in the gap, being forced out of the gap owing to the creeping tendency of the material of which they consist, the unit is constructed in such a way that the gap is shut off on the side of the pierced part of the cup-shaped sheaths, while on the other side the sheaths are kept under pressure by a compression spring 8 mounted in that place between rings 7 fitting into the gap.

In FIG. 1 the insulating parts 1 and 2 each may be a part of a section of a switching device which may be separated by moving them apart. The embedded conductors 3 may be connected to the supply terminals of the switch, while the conductors 4 are bus conductors connecting the conductors 3 of successive sections of the switching device. The connection shown in FIG. 1 is assembled by fi-rst applying the sheaths or sleeves 6 and eventually the spring 8 on the insulating member 5 of the bu conductor 4, then placing this construction between the moved apart insulating parts 1 and 2 and finally moving these parts towards each other to the positions shown inthe figure.

FIG. 2 shows the conection of three cables 11, not filled with oil, with three conductors 13 extending beyond the insulating part 12 of a three-phase high voltage apparatus for instance. Wherever the connecting members between the cable cores and the conductors 13 are of no further interest for the invention, they are not shown.

In order to safeguard the connections between these high-voltage conductors, located at short distances from shaped filler sheaths 15.

each other against contact as well as against spark-over among the conductors each of them is surrounded by a cylindrical sleeve 14 of insulating material extending from the insulation of the conductors 13 to beyond the cable insulation. The sleeves 14 have been pushed tightly on the cylindrical end portions of the insulating part 12, which have previously been fitted with lightly greased cup- Here too the air between the filler sheaths 15 and the insulating parts 12 and 14 has been expelled owing to the fact that the outer diameters of the end portions with the sheaths have been chosen larger than the inner diameters of the sleeves. .In the place where the sides of the cup-shaped filler sheaths 15 merge into the pierced bottom portion the sleeves 14 are slightly narrowed, so as to keep the sheaths pressed against the end portions.

' In FIG. 2 the conductors 13 may be the terminals protruding from the insulating body 12 of a switching device and which are to be connected to the cables 11. In order to avoid sparkover between the cable connections each connection is surrounded by a cylindrical sleeve 14. This structure is assembled by applying sheaths or sleeves 15 on the cylindrical end portions of the body 12 and sleeves 15 around the respective cables 11 and then, after the connection has been made, pushing the sleeves 14 over the sheaths 15 on the body 12.

Although thi is not shown in the drawing, it will be obvious that here too the riskof the filler being forced out of the gap can be prevented by shutting oiT the gap,

. for instance, at the lower end and mounting above each .filler sheath round the end portion in question a ring fitting into the gap and containing a compression spring. In order to shut off the gap, the part of the sleeve enclosing the sheath may,jfor instance, also be cup-shaped, the bottom part being equipped with a raised edge which fits against the lower side of the end portion. 1

The sleeves 14 are further equipped with an outwardly extending flange 16 with which they rest on an inwardly extending part of a protective cap 17 consisting of two portions and surrounding the whole unit. This cap grips about the outwardly extending flange 18 of the insulating part 12 and is kept in place by pins 19 fitted in lugs of the part 12.

What we claim is:

1. A semi-permanent connection between electrically insulated high-voltage conductors comprising insulating parts surrounding the conductors and separated by a gap containing a member of flexible insulating material held under pressure in said gap, the insulating parts having constant transverse dimensions over the entire length of the gap formed between them, the insulating member consisting of a filler sheath in the form of a sleeve covering the inner insulating part and being anchored to the free end thereof, said sheath having outer dimensions larger than the inner dimensions of the outer insulating part, the insulating parts being joined together by compression, in the gap so that the air between this sheath and the insulating parts is permanently expelled.

2. A emi-permanent connection according to claim 1, in which the gap between the insulating. parts form a space that is closed at least at one end and in which a compression spring is provided in the space to maintain the filler sheath under pressure in said space.

1 3. A semi-permanent connection according to claim 1, in which the filler sheath is cup-shaped with the bottom of the cup forming the anchorage.

References Cited by the Examiner UNITED STATES PATENTS 2,280,711 4/1942 Machlett et al 174-75 X 2,857,557 10/1958 Imhof. 2,894,054 7/1959 Cameron et al 17473 X LEWIS H. MYERS, Primary Examiner.

JOHN P. WILDMAN, ROBERT K. SCHAEFFER,

JOHN T. BURNS, Examiners.

D. L. CLAY, Assistant Examiner. 

1. A SEMI-PERMANENT CONNECTION BETWEEN ELECTRICALLY INSULATED HIGH-VOLTAGE CONDUCTORS COMPRISING INSULATING PARTS SURROUNDING THE CONDUCTORS AND SEPARATED BY A GAP CONTAINING A MEMBER OF FLEXIBLE INSULATING MATERIAL HELD UNDER PRESSURE IN SAID GAP, THE INSULATING PARTS HAVING CONSTANT TRANSVERSE DIMENSIONS OVER THE ENTIRE LENGTH OF THE GAP FORMED BETWEEN THEM, THE INSULATING MEMBER CONSISTING OF A FILLER SHEATH IN THE FORM OF A SLEEVE COVERING THE INNER INSULATING PART AND BEING ANCHORED TO THE FREE END THEREOF, SAID SHEATH HAVING OUTER DIMENSIONS LARGER THAN THE INNER DIMENSIONS OF THE OUTER INSULATING PART, THE INSULATING PARTS BEING JOINED TOGETHER BY COMPRESSION, IN THE GAP SO THAT THE AIR BETWEEN THIS SHEATH AND THE INSULATING PARTS IS PERMANENTLY EXPELLED. 